boost::asio::steady_timer基础使用

最新推荐文章于 2025-07-14 19:20:51 发布

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本文详细介绍了C++中定时器的演变过程，从早期的boost::asio::deadline_timer到更符合C++标准的boost::asio::steady_timer。通过实例代码展示了如何使用steady_timer进行异步等待和时间控制。

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看到书上说，boost::asio::deadline_timer是asio早期版本提供的定时器，使用boost.date_time库提供时间支持。貌似deadline_timer会被逐渐淘汰。所以学了一下更符合C++标准的steady_timer，

//boost::posix_time::to_simple_string函数需要这两个头文件
#include <boost/date_time.hpp>
#include <boost/date_time/posix_time/ptime.hpp>
//使用boost.chrono代替std.chrono,
#define BOOST_ASIO_DISABLE_STD_CHRONO
#include <boost/asio.hpp>
#include <boost/asio/steady_timer.hpp>
#include <boost/asio/placeholders.hpp>
#include <boost/thread.hpp>

class MyClass
{
public:
    MyClass() :m_work(m_io), m_timer(m_io){}
public:
    boost::thread_group m_thgp;
    boost::asio::io_service m_io;
    boost::asio::io_service::work m_work;
    boost::asio::steady_timer m_timer;
public:
    void Init()
    {
        boost::system::error_code errCode;
        m_thgp.create_thread(boost::bind(&boost::asio::io_service::run, boost::ref(m_io), errCode));
        std::cout << "Init_1, " << LocalTime() << std::endl;
        m_timer.expires_from_now(boost::chrono::milliseconds(4000)); //设置过期时间长度
#if 0
        m_timer.expires_from_now(std::chrono::milliseconds(4000));
#endif
        std::cout << "Init_2, " << LocalTime() << std::endl;
        m_timer.async_wait(boost::bind(&MyClass::Test, this, boost::asio::placeholders::error));//异步等待
        std::cout << "Init_3, " << LocalTime() << std::endl;
        //由Console可知, 函数立即返回了, 定时器的expires_from_now是由完成端口处理的
    }
    void Stop()
    {
        std::cout << "Stop_1, " << LocalTime() << std::endl;
        m_timer.cancel();  // 取消所有handler
        m_work.~work();
        m_thgp.join_all();
        std::cout << "Stop_2, " << LocalTime() << std::endl;
    }
    static std::string LocalTime()
    {
        return boost::posix_time::to_simple_string(boost::posix_time::microsec_clock::local_time());
    }

    void Test(const boost::system::error_code& ec)
    {
        printf("test_1, %s, ec.value=%d, ec.message=%s\n", LocalTime().c_str(), ec.value(), ec.message().c_str());
        if (ec)  return;
        m_timer.expires_from_now(boost::chrono::milliseconds(4000));
#if 0
        m_timer.expires_from_now(std::chrono::milliseconds(4000));
#endif
        std::cout << "test_2, " << LocalTime() << std::endl;
        m_timer.async_wait(boost::bind(&MyClass::Test, boost::ref(*this), _1));
#if 0
        m_timer.async_wait(boost::bind(&MyClass::Test, this, _1));
        m_timer.async_wait(boost::bind(&MyClass::Test, this, boost::asio::placeholders::error));
#endif
        std::cout << "test_3, " << LocalTime() << std::endl;
    }
};

int main(int argc, char** argv)
{
    MyClass my;
    my.Init();
    for (int i = 0; i < 30; ++i)
    {
        boost::this_thread::sleep_for(boost::chrono::milliseconds(1000));
    }
    my.Stop();
    std::cout << "press ENTER to exit..." << std::endl;
    std::cin.sync();
    while (getchar() != '\n') {}
}

完。